Suction roll



March 3, 1942. 'E ABBOTT ET AL 2,274,641

SUCTION ROLL 7 March 3, 1942. AB OTT ETAL 2,274,641

SUCTION ROLL Filed Feb. '7, 1938 i 2 Sheets-Sheet 2 Patented Mar. 3, 1942 SUCTION ROLL Ernest J. Abbott and John D. Kraus, Ann Arbor, Mich.; said Kraus assignor to said Abbott Application February 7, 1938, Serial No. 189,043

14 Claims.

This invention relates to suction rolls and has special reference to the combination therein of means for silencing the operation thereof and for eliminating the particularly offensive sound caused thereby.

The invention is directed to the problem of eliminating the noise or sound incidental to the operation of high speed modern suction rolls of the type in which the holes in the shell 'are frequently small in diameter and relatively long, the shell travels at high speed and relatively high vacuums are employed. In the development of the art, as the shells of the rolls have been made Figure 1 is a transverse section through a suction roll embodying our invention;

Fig. 2 is a fragmentary section similar to Fig,- ure 1 showing the packing and shell at the oncoming side of the suction chamber in substantially full size;

Fig. 3 is a fragmentary view similar to Figure 1 showing the parts at the offgoing side of the suction box in substantially full size;

Fig. 4 is a view similar to Fig. 2 showing a second strip adjacent the packing strip adapted thicker, the speeds higher and the vacuum greater, the sound created by the rolls has become progressively more objectionable until at the present time-the-s'ituation has become so aggravated as to interfere with the physical well being and the efiiciency of the workmen. The pitch and character of the sound is such as to be particularly aggravating and the characteristic whine or siren type sound has now become familiar in the environment of paper mills and can be heard for a considerable distance around'the mill.

We are aware that attempts have'been made to accomplish a solution of the problem, notably by Berry, Hombostel and Goodwillie, as shown in to control the flow of air;

Fig. 5 is a view similar toFig. 3 showing'a modified form of silencing device;

Fig. 6 is a fragmentary section through a suction roll showing a construction in which the position of the packing strip may be adjusted to V control the flow of air;

their Patent No. 2,107,812, over which this invention is an improvement. However, such attempts have not been entirely successful. While the devices therein shown are effective to eliminate the of 90%, which may be a sufficient. reduction in many cases, yet in aggravated cases there may still remain a material residue of sound sufficient to be highly aggravating.

The primary object of this invention is the provision of a suction roll construction wherein the sound caused by the movement of air with respect to the holes of the shell is substantially entirely eliminated, in most cases-being reduced to less than 1% of the sound energy which would otherwise be produced, and to provide a simple, efficient and adjustable construction for accomplishing this result. We have also aimedto provide a suction roll construction wherein the suction, box packing is caused to control the flow of air between the holes of the shell and the atmosphere into which the holes open so as to prevent the production of sound.

Other objects and advantages will be apparent from the following description and the accompanying drawings, in which--- sound in substantial part, possibly to the extent Fig. 7 is a fragmentary section through a suction roll showing a modified form of means for adjusting the packing;

Fig.8 is a section on the line 8-8 of Fig. 7, and

Fig. 9 is a fragmentary section showing a wide packing strip.

Referring first to Figure 1, we have shown a portionof a suction roll embodying our invention. This consists of an outer shell 9 of conventional nature having the usual perforations or holes I I for transmitting the vacuum through the shell to the paper stock l2 carried on the usual felt or wire l3 in contact with the outer surface of the roll in the usual manner. The shell moves in the direction indicated by the arrow in this as well as in the other views. The roll has a suction box l4 positioned within the shell which carries a packing holder i5. Spring members l6 and I! on opposite sides of the packing holder urge the packing against the inner surface of the shell. The packing holder l5 carries two packings l8 and I9 adjacent opposite sides thereof defining a, vacuum chamber 2| extending longitudinally of the roll. The chamber 2| communicates with the interior of the suction box It through a plurality of ports 22 spaced longitudinally of the suction box. The parts described represent a substantially conventional suction roll construction commonly used in combination with suitable high capacity vacuum pumps arranged to maintain a relatively high vacuum within the suction box [4 and the chamber 2|. v

The'jsound generated by a roll of this type is produced by'pressure waves generated when a volume of air is suddenly placed in communicationwith another volume of air at different pressure. Such'd-iscontinuities of pressure occur, we

have found, at. two pointsfirst, when holes containing air at atmospheric pressure come into communication with the suction chamber 2| as .the holes pass over the inner edge of the packing l8, and second, when the holes containing air at the suction box. pressure come into communication with atmospheric pressure as they pass over the' outer edge of the packing l9. Usually, the latter discontinuity is more important in producing sound externally to the machine, but

we have found-that when this is properly quieted, the source at the oncoming side of the suction box becomes important and that both must be treated in order to obtain the substantially com:-

plete elimination of the sound. According to our invention, quieting of the roll is achieved by providing a'gradual change of pressure during the interval that the holes are coming into and out of registration with the suction chamber so that by the time they have reached the edge of the packing, the pressure in the holes has reached that of the volume of air with which the holes then'communicate. We have found at its source, and measurementshave shown that .by this means the sound energy emitted by the roll can be reduced by more than 99%,-or in other words, to less than 1% of its original value.

the shell throughout the entire width of its upthat this method effectively reduces the sound The gradual changes of pressure for quieting I operation of the roll may be provided either by modifying the shape of the packing itself or providing auxiliary means adjace t the packing for accomplishing this purpose, a d in either case the means for accomplishing the purpose may be fixed or adjustableto suit conditions or the desires of the operator. In Figs. 1 to 3, inclusive, we have shown a non-adjustable form. As will be seen from Fig.2, the packing. I? at the on coming side of the suction chamber 2! is fixedly secured in the holder l5 by means'of cap screws 23. The outer surface of the packing I8, which may be any of a number of materials well known in the prior art, such, for example, as woodor micartafl is not shaped .to conform with the inner surface of theshell 3 as in conventional practice, but instead is formed so that the outer or oncoming corner 24 thereof abuts against the inner surface of the shell and the inner corner is spaced from the surface of the shell as shown at 25, the outer surface of the strip sloping toward the shell as shown at 26 to provide a tapering space between the inner surface of the shell and the outer surface of the packing strip, conproperly balanced with respect to the size of the shell holes, the speed of'the shell and other factors. This slot may be in the form of a long slot extending longitudinally of the packing, or in the form of grooves extending inward from the oiTg oing side of the packing spaced longitudinally of the packing so as to be in registration with each row of holes in the, shell.

Referring now to Fig. 3, it will be seen that this same principlehasbeen applied to the offgoing side of the suction box. In this instance the packing l9 consists of two strips 28 and 29 v of suitable packing material (though they can as well be made of a single strip properly formed) secured to the packing holder by cap screws 3|. The strip 28 conforms to the inner surface of per edge while the strip 23 is relieved or gradually recedes therefrom as 'shown' at 32 to provide the restriction 21 heretofore described. Through this construction the seal formed in the conven- 'tional way by the packing strip 28 is undisturbed and functions throughout the width of the strip.

This in effect constitutes merely a wider or thicker packing strip but may be of slightly greater convenience because of being formed from two independent strips 28 and 23.

For example, in one physical embodiment of the invention the packing'strips were made in accordance with Figs. 3 and 4 with the excep- -tion that the strips 23 and 23 were formed as a single piece, and the strips 33 and 34 were a single piece. Each of the strips were 2" thick which gave an are approximately 2%" long. A" of thisdistance conformed with the shell contour, while the remainder was tapered to give an' opening of at the oifgoing edge. Th roll was a 30"diameter roll of 2 shell thickness, and the holes ,were A," in diameter. The vacuum was about 18" of mercury, and the speed of the felt was about 1500 feet per minute.

As shown in Fig. 4, the packing strip at the oncoming side of the suction box may be formed in the same manner as that shown in Fig. 3.at the ofigoing side by providing a packing formed of two strips 33 and 34 secured to the holder by means of cap screws 35, the upper edge of the packing 33 conforming through its width with the inner surface of the shell 3, and the strip 34 diverging therefrom as shown at. to provide the vent passage 21.

Referring now to Fig. 5, we have therein shown a modified form of the invention wherein an verging toward the outer comer of the strip.

provides a wedge-shaped air space forming a vent or graduated restriction 21 which comficiently small to care for most variations in these factors. It is furthermore not essential that the space be tapered or graduated, but it may be a slot of uniform cross-section as shown at 20 in Fig. 9 if the distance between the inner surface of the shell and the opposed-surface of the slot together with the width of the slot be municates at its larger end with the volume into auxiliary element or lipis provided adjacent the packing, and means are provided for adjusting the angle of divergence between the inner surface ofthe shell and the surface of the lip to bring about optimum silencing conditions and to compensate for wear on the packing strip. In

this form of the invention the packing strip 31 is in contact with the inner surface of the shell throughout the entire width of its upper edgeand carries an adjustable lip 38. The lip '38 is carried on a plurality of brackets 39 having fingers 4| seated in the side of the strip and pivotally carried on'a pin 42 extending longitudinally of the strip 31'. The brackets 33 are spaced longitudinally of the strip 33 so as to provide suitable support. In the case of very short rolls, the brackets may be at the endsof the strip. Interposed between the lip 38 and the strip 31 is a rod 43 of resilient rubber seated in arcuate depressions 44 and 45 of the lip and strip for the purpose of sealing the junction between the lip and the strip. The lower ends of the brackets 39 have arms 46, and springs 41 are interposed between the packing holder l and the arms, tenadjusted with respect to the inner surface of the shell so as to bring about and maintain the proper vent passage. In Fig. 6 we have shown a construction in which the packing holder is altered somewhat from thatshown in Figurel in .that arcuate upper surfaces 5| are provided for the purpose of supporting the packing strips. In this case a packing strip 52 is carried in a base member v53 having an arcuate surface 54' complemental to the surfac 5|, the curvature of the arcuate surfaces being such that when the base member 53 is rotated in a plane parallel with Fig. 6, the inner comer 55'of the packing strip in contact with the inner surface of the shell will remain stationary and the thickness at the open end of the vent passage 21 will be varied. The

packing holder has slots 58 for the passage of.

rods 51, the base 53 being held against its seat by springs 58 acting between the washers 59 seated against pins 8| in the rods 51 and washers 82 seated against the lower surface of the packing holder. The lower ends of the pins 51 are slotted as shown at 83 for the reception of nuts 84 pivotally supported therein by pins 85 seated in slots 65. Screws 61 are seated in the packing holder and received in the nuts 64 so that upon rotation the nuts will travel along the screws, thus moving the base member 53 along the armate seat 5| to tilt the packing strip. The screws 61 also carry worm gears 88 adapted to cooperate with worms 89 carried on and driven by a flexible shaft 1| whereby .rotation of the shaft brings about tilting of the packing strip in the fashion described. The shaft 1| can be rotated from a point beyond the end of the suction box It in the manner which will be described in connec tion with Fig. '1. It will be seen that with this construction the character of the vent passage 21 may be varied to produce optimum silencing conditions by tilting of the packing strip without in any way disturbing the roll and from a point outside the roll, and while the roll is in operation.

' In Fig. '1 we have shown a still further apparatus for supporting the packing strip to tilt the same in order to adjust the characteristics of the vent passage 21. While this View shows the construction in use at the ofigoing side of the suction box, it will be apparent that this construction as well as that .shownin' Fig. 6 may likewise be employed at the oncoming side of the suction box. In this form the suction box has a channel 12 base member by means of cap screws 83, the upper edge thereof normally diverging from the inner surface of the shell so as to provide the vent passage 21. her 19 has spaced ears 84 and 85 spaced longitudinally thereof'between which is receiveda nut 86 having laterally extending pins 81 and 88 seated in slots 89 and 9| of the ears as shown in Fig. 8.. The nuts 86 receive threaded rods 92 carried in the holder 14 in such manner that upon rotation of the rods the packing is tilted so as to vary the characteristics of the vent passage 21.

The rods 92 carry worm gears 93 adapted to mesh with worms 94 carried on a flexible shaft 95 supported on the holder 14 by means of ears 96 and passing through the end 91 of the suction box,

the flexible connection such as flexible shaftingpermitting relative movement between the end of the suction box and the shaft 95 whereby to permit of movement of the packing holder. A crank 98 is connected to theshaft externally of I thesuction box so that upon rotation of the crank the nuts 86 are'moved longitudinally of the rods 92 and the packing tilted with respect to the irmer surface of the shell, therebyyarying the vent passage .21 to obtain optimum silencing conditions.

Attention is directed to the numerous andmanifest advantages of the invention, most important of ,which is the fact that substantially complete quieting of the disturbing sound of the suction roll is obtained, the sound energy being reduced to 1% or less of that which would normally be produced by the roll. This may be accomplished if desired without adding additional parts of any kind to the suction roll, that is, by merely relieving .the customary packing ,at the offgoing side of the packing either at the oncoming side of the suction box, the offgoing side of the suction box, or both. We have also shown means whereby the result may be accomplished without in any way changing the sealing proper-- ties of the conventional packing strip by increasing the thickness of the packing strip through the addition of a second strip parallel to and in contact with the conventional packing strip. We

have also shown constructions whereby the silenc-' ing means may be adjusted from the exterior of the roll and while the roll is in operation in order to produce the optimum operation conditions.

We have accomplished the substantial silencing of the roll by eliminating the sound at its source;

. in other words, by actually preventing the production of sound through preventing sudden dis-' within which is carried a flexible rubber supportcontinuities of pressure. The gradual changes of pressurenecessary to quiet the operation of the roll may be provided by modifying the shape of the packing, by, providing on the entering side of each packing strip a section whose shape conforms to that of the inner surface of the shell to form a bearing area between the packing and the shell and provide a suitable seal for the vacuum.

on the inside of the suction box. The remainder of the width of the packing is relieved or modified in such manner as to provide a vent passage,

preferably a graduated restriction communicating 'at its larger end with the volume (either within the suction box or on the exterior thereof) on the leaving side of the packing. As the holes pass the packing. strip, they are first sealed off from the pressure at the entering side, and then connected to the leaving side by means of a thin passage which greatly restricts the flow of air and thus prevents discontinuities of pressure with their attendant radiation. As the holes progress The lower surface of the base mem- 1 whichacross thepacking strip, the resistance to the flow of air tending to equalize the pressure becomes less and-less, due to both a shortening of the length of the path and to an increase in the width of the connecting passage so that when the holes break free of the packing strips, the pressure within the holes has reached substantial uniformity with that of the volume into which they come into communication. I

This arrangement precludes any possibility of discontinuities in pressure, and measurements show that it is effective over a wide range of operating conditions. In many respects it is selfcompensating for different factors. For example, i

an increase in pressure difierence, increases the rate of flow, and thus tends to equalize the pressure in about the same time as with smaller pressures. Similarly, an increase in the volume of the holes, or of leakage into the holes through the felt or wire, increases the pressure within the hole at a given point of its passage past the packing, and this additional pressure affects the flow so as to offset the effect 'of the increased volume or leakage. If the speed of the roll is decreased, equilibrium of pressure is achieved before the holes have completed their passage across the packing, but as the time of transit is longer, the change of pressure still takes place at about the same rate. Measurements show that silencing lips of this type are effective over wide ranges of speed, vacuum, and shell dimensions.

Where in this application we refer to the packing strip as being of relatively inelastic material, we mean a material which is sufllciently hard and inelastic that it will not be distorted into. the holes of the shell under the seating pressure applied to the packing strip or under the vacuum of the holes. I

It will be understood that the specific embodiments herein shown are by way of illustration and not by way of limitation,'-'and that we do not wish to be limited except as required by the prior art and the scope .of the appended claims, in

We claim: I

1. The combination in a suction roll of a perforate shell having v.a plurality of holes, a suction box for applying reduced pressure to said -holes,' 'a seal between the suction box and the inner surface of the shell defining areas of pres- I sure cliange in said holes, means located at the the flow of air with respect to the perforations and thereby prevent the production of sound.

3. The combination in a suction roll of a perforate shell, a suction box, a normally stationary packing of relatively inelastic material acting therebetween, said packing having a portion at the oncoming side thereof in contact with the inner surface of the shell to form a seal, the packing diverging from said surface toward the ofigoing side thereof to provide a vent passage of relatively great width with respect to thickness for controlling the flow of air with respect to the perforations and thereby prevent the production of sound, and means for tilting the packing to vary the angle of said divergence.

4. The combination in a suction roll of a perforate shell, a suction box, a packing acting therebetween, said packing having a portion at the oncoming side thereof in contact with the inner surface of the shell to form a seal, the packing diverging from said surface toward the offgoing side ,thereof to provide a vent passage for controlling the flow of air with respect to the perforations and thereby'prevent the production of sound, means for tilting the packing to vary the angle of said divergence, and means for actuating said tilting means from outside the roll while the shell is rotating.

5. The combination in a suction roll of a perforate shell, a suction box, a normally stationary packing acting between the suction box and the inner surface of the shell to form a seal, a silencing member attached adjacent to said packing and having sealed contact thereagainst, said member having a face opposed to the inner surface of said shell diverging from the shell to provide a graduated restriction of relatively great width with respect to thickness for the flow of air into the perforations to prevent the production of sound, and means for pivotally supporting said member for rotation toward and away from the shell to adjust the angle of divergence.

6. The combination in a suction roll of a perforate shell, a suction box, a normally stationary packing acting between the suction box and the inner surface of the shell to form a seal, a silencing member attached adjacent to saidpacking and having sealed contact thereagainst, said member having a face opposed to the innersurface of said shell diverging from the shell to provide a graduated restriction of relatively great width with respect to thickness for the flow of air, to prevent the production of sound, means for tilting the silencing member to vary the angle of said divergence, stop means for predetermining' the position of said member, and spring means for maintaining said member against said stop means. '7. The combination in a suction roll of a perforate shell, a suction box, a packingacting between the suction box and the inner surface of tionary packing strips of relatively inelastic material acting between the suction box-and the inner surface of the shell defining a suction chamber, each of said packing strips having a portion at the oncoming side thereof in contact with the'inner surface of the shell to form a seal, the packing diverging from said surfaceto ward the oifgoing side thereof to provide a slender tapering vent passage of relatively great width with respect to thickness for controlling the shell to form a seal, a silencing member pivotally attached adjacent to said packing and having sealed contact thereagainst, said member having a face opposed to the inner surface. of said shell diverging from the shell at a small angle to provide a'graduated restriction of relatively- Bptimum sound eliminating angle of divergence therefor.

8. The combination in a-suction roll of a perforate shell, a suction box, a packing holder on 2,274,641. the suction box, a normally stationary packing strip adapted'to abut against the inner surface of the shell, said strip having a portion at the oncoming side thereof in contact with the inner surface of the shell to form a seal, thestrip diverging from said surface towardtheofigoing side thereof to provide a vent passage of gradually increasing thickness and of relativelygreat width with respect to thickness for. restricting the initial flow of air'to the perforations and thereby prevent the production of sound, means for supporting the packing strip on the packing'holder, and meansfor adjusting the angular position of said last mentioned means with respect to saidto the perforations, means for moving said sup port on'sai'd arcuate seattotilt the packing and thereby vary the angle of divergence to an optimum silencing, angle, and spring means for maintaining said packing supportagainst said seat,

- 12. The

combination in a s'uction' roll of a perforate shell, a suction box, a packing holder'hav-' ing an arcuate seat, apacking support having an arcuate surface complemental to said seat, a) packing in said support having an oncomin edge bearing against the inner surface of said shell to provide a 'seal, the packing diverging from the inner surface ofthe shell toward the oligoing edge of the packing to providea vent passage for controlling the flow of air with respect to the perforations, means for moving said support on said arcuate seat to adjust the angularity of the packing and thereby vary the angle angle from the inner surface of the shell toward the oiigoing edge of the packing to provide a vent passage of relatively great.width with respect to thickness for controlling the flow of air.

with respect to the perforations, and means for moving said support on said arcuate seat to adjust'the position of the packing to vary-the angle of divergence to an optimum silencing angle. 4

10. The combination in a suction roll of 'a perforate shell, a suction --box, a packing holder having an arcuate seat, a packing support having an arcuate surface complemental to said seat, a packing in said support having an oncoming edge -bearing against the innersurface of said shell to provide a seal,'said arcuate seat and said surface being generated on an are about the point of contact between the oncoming edge'of said packing and the surface of said shell, the packing diverging from the inner surface of the shell toward the 'offgoing edge of the packingto provide a vent passage for controlling thefiow of air with respect to the perforations, and means for moving said support on said arcuate, seat to adjust the angularity of the packing andthereby vary the angle of divergence .to an optimum,

silencing angle.

11. The combination in a suction roll of a pertion of travel of said shell for, controlling the forate shell, a suction box, a packing holder ha'ving an arcuate seat, a packing support having an arcuate surface complemental to said seat, a normally stationary packing in said support having an oncoming edge bearing against the inner surface of said shell to provide a seal, the packing diverging at a small angle from the inner surface of-the shell toward the ofigoing edge of the packing to provide a restricted vent passage of relatively great width with respect to thickness for controlling the flow of air with respect of divergence to an optimum silencing angle, a

plurality of screws acting ,between said packing holder and said packing support for adjustingthe angle of divergence between the packing and the shell, and means for actuating said screws from a point outside the suction roll.

13. The combination in a suction roll of a perforate shell, a suction box, a, packing holder, a packing support, means for pivotally carrying said packing support on said packing holder, a packing in said support having'an oncoming edge bearingagainst the inner surface of said shell to provide a seal, the packing diverging from the inner; surface of the shell toward the ofigoing edge of the packing toprovide a vent passage of gradually increasing thickness in the direcflow of air with respect to the perforations, and

means for rotating said support about saidpivotal point to adjust thetposition of the packing and thereby, vary the angle of divergence to an optimum silencing angle. 7

14. The combination in a suction roll of a perforate shellcra suction box, a packing holder, a packing support means for pivotally carrying saidpacking support on said packing holder, a packing in said support having an oncoming edge bearing" against the inner surface of said shell to provide a seal; the packing diverging from the innersurface of the shell toward the offgoing.

edge of the packing-to provide a vent passage for controlling the flow of air with respect to the perforations, means for rotating said support about said pivotal point to adjust the angularity ,of the packing and thereby vary the angle of divergence to an optimum silencing angle, a plurality of screws acting between the packing holder and said packing support for adjusting the angle of divergence, and flexible shaft means extending. to a stationary point outside the suction roll'for turning said screws to adjust the angular position of the packing support.

. ERNEST J; ABBOTT. JOHN D. KRAUs. 

